α2M can bind to a range of endogenous disease-associated proteins including the amyloid β peptide (Aβ1–42) [6], prion proteins [7] and β2-microglobulin [8], which are the main components of deposits found in Alzheimer’s disease (AD), spongiform encephalopathies and dialysis-related amyloidosis, respectively [9]. Here, PRNP is linked to Alzheimer disease.